[PATCHv3 5/6] arm64: Always keep DAIF.[IF] in sync

[Will Deacon]

On Mon, Mar 15, 2021 at 11:56:28AM +0000, Mark Rutland wrote:
> From: Hector Martin <marcan at marcan.st>
> 
> Apple SoCs (A11 and newer) have some interrupt sources hardwired to the
> FIQ line. We implement support for this by simply treating IRQs and FIQs
> the same way in the interrupt vectors.
> 
> To support these systems, the FIQ mask bit needs to be kept in sync with
> the IRQ mask bit, so both kinds of exceptions are masked together. No
> other platforms should be delivering FIQ exceptions right now, and we
> already unmask FIQ in normal process context, so this should not have an
> effect on other systems - if spurious FIQs were arriving, they would
> already panic the kernel.
> 
> Signed-off-by: Hector Martin <marcan at marcan.st>
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Tested-by: Hector Martin <marcan at marcan.st>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: James Morse <james.morse at arm.com>
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: Thomas Gleixner <tglx at linutronix.de>
> Cc: Will Deacon <will at kernel.org>
> ---
>  arch/arm64/include/asm/arch_gicv3.h |  2 +-
>  arch/arm64/include/asm/assembler.h  |  8 ++++----
>  arch/arm64/include/asm/daifflags.h  | 10 +++++-----
>  arch/arm64/include/asm/irqflags.h   | 16 +++++++---------
>  arch/arm64/kernel/entry.S           | 12 +++++++-----
>  arch/arm64/kernel/process.c         |  2 +-
>  arch/arm64/kernel/smp.c             |  1 +
>  7 files changed, 26 insertions(+), 25 deletions(-)

Acked-by: Will Deacon <will at kernel.org>

Will